# Set defaults for a part of Symbolics.Arr

**URL:** https://discourse.julialang.org/t/set-defaults-for-a-part-of-symbolics-arr/119678
**Category:** Modelling & Simulations
**Tags:** question
**Created:** [September 21, 2024, 3:43pm UTC](https://discourse.julialang.org/t/set-defaults-for-a-part-of-symbolics-arr/119678 "2024-09-21T15:43:13Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Bart\_van\_de\_Lint](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bart_van_de_lint/32/212161_2.png) [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)
#### Post date: [September 21, 2024, 3:43pm UTC](https://discourse.julialang.org/t/set-defaults-for-a-part-of-symbolics-arr/119678/1 "2024-09-21T15:43:13Z")

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Is it possible to set defaults for only a part of a Symbolics.Arr when defining a model? So can I for example only set defaults for pos[:, 4:8], while not setting defaults for pos[:, 1:3] and pos[:, 9:10]?

```julia
  @variables begin
        pos(t)[1:3, 1:10] = pos_
  end

```

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<div class="post-metadata">

### Author: ![Bart\_van\_de\_Lint](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bart_van_de_lint/32/212161_2.png) [@Bart\_van\_de\_Lint](https://discourse.julialang.org/u/Bart_van_de_Lint)
#### Post date: [September 21, 2024, 3:51pm UTC](https://discourse.julialang.org/t/set-defaults-for-a-part-of-symbolics-arr/119678/2 "2024-09-21T15:51:30Z")

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Solution: just set the parts of the array you don’t want to have defaults to nothing.